19. a certain chain saw requires a fuel mixture of 5.5% oil and the remainder gasoline. how many liters of 2.5% mixture and how many of 9% mixture must be combined to produce 40.0 liters of 5.5% mixture?
a. 12 4/23 liters of 2.5% and 28 19/23 liters of 9% b. 28 19/23 liters of 2.5% and 12 4/23 liters of 9% c. 21 liters of 2.5% and 18 liters of 9% d. 18 6/13 liters of 2.5% and 21 7/13 liters of 9% e. 21 7/13 liters of 2.5% and 18 6/13 liters of 9% f. 18 7/13 liters of 2.5% and 21 6/13 liters of 9%
20. mary can row at the rate of 4 miles per hour in still water. rowing downstream in a river, she can travel 3 times as far in 1 hour as she can rowing upstream. what is the rate of flow in the river?
a. 1 miles per hour b. 2.5 miles per hour c. 4 miles per hour d. 2 miles per hour e. 3.5 miles per hour f. 3 miles per hour
